A library apparatus is known as an external bulk storage that is used while being connected to a mainframe computer. A magnetic tape library apparatus is an example of a library apparatus.
Such a magnetic tape library apparatus generally includes storage units (magazines) which each store multiple magnetic tape cartridges that house magnetic tape media, a conveying mechanism that conveys the magnetic tape cartridges, and a magnetic tape drive that reads and writes data to and from the magnetic tape media.
The magazines in the magnetic tape library apparatus are individually operated and managed by an operator. Therefore, the magazines are structured such that they may be pulled out or detached from the magnetic tape library apparatus when the operator replaces the magnetic tape cartridges. However, the manner in which the magazines are handled differs depending on the operator, and there is a possibility that the magazines will be handled in a manner unexpected by the designer.
In addition, each magazine has openings through which the magnetic tape cartridges are inserted and extracted in a side surface thereof, and is therefore to be handled such that the openings do not face downward and the magnetic tape cartridges do not fall from the magazine. If the operator carries the magazine such that the openings face downward by mistake, there is a risk that the magnetic tape cartridges will fall from the magazine to the floor. In such a case, there is a possibility that the magnetic tape cartridges will be damaged and important data stored therein will be lost.
Accordingly, a technology for preventing the magnetic tape cartridges from falling from the magazine by providing a lock mechanism that locks the magnetic tape cartridges in the magazine has been proposed (see, for example, International Publication Pamphlet No. WO2006/103735 and Japanese Laid-open Patent Publication No. 10-241238).
FIGS. 18A and 18B are diagrams illustrating a known lock member. FIGS. 18A and 18B illustrate a cell 81 that serves as a storage section in a magazine. FIG. 18A illustrates a locked state in which a cartridge 80 is locked in the magazine (cell 81).
A lock member 83 is provided on a side wall surface 81h of the cell 81. The lock member 83 is fixed to the side wall surface 81h of the cell 81 with a fixing portion 82 provided at an end of the lock member 83. The lock member 83 includes an arm portion 84 that has spring characteristics. An engagement portion 85 that engages with an engagement groove 80m formed in the cartridge 80 is provided at an end of the arm portion 84. When the engagement portion 85 engages with the engagement groove 80m, the cartridge 80 is locked in the magazine (cell 81).
FIG. 18B illustrates the manner in which the cartridge 80 is inserted into or extracted from the cell 81 in the direction indicated by arrow A (insertion-extraction direction). FIG. 18B illustrates an unlocked state in which the cartridge 80 is not locked in the magazine (cell 81).
When the cartridge 80 is inserted into the cell 81, the engagement portion 85 of the lock member 83 is pushed by the cartridge 80 and is moved outward through an opening 81k formed in the side wall surface 81h of the cell 81. Then, when the engagement portion 85 faces the engagement groove 80m, the engagement portion 85 is returned to the original position by the elastic force generated by the arm portion 84. Accordingly, the engagement portion 85 engages with the engagement groove 80m and the cartridge 80 is locked in the magazine (cell 81).
When the cartridge 80 is extracted from the cell 81, the cartridge 80 is pulled by a force larger than a frictional resistance (locking force) between the engagement portion 85 and the engagement groove 80m. Accordingly, the engagement portion 85 of the lock member 83 is pushed by the cartridge 80 and is moved outward through the opening 81k formed in the side wall surface 81h of the cell 81. Thus, the engagement portion 85 is disengaged from the engagement groove 80m and the cartridge 80 is released from the locked state.
With regard to the above-described lock member, it is desirable to effectively design the locking force of the lock member to ensure the reliability of the locked state. However, in practice, there are variations in the surface state of the cartridge, the shape of the engagement groove, the frictional resistance between the engagement portion and the engagement groove, etc., and high-level analyses are preferably performed to design the locking force.
Accordingly, the reliability of the locked state may be increased by increasing the locking force applied by the lock member. However, if the locking force is increased, a hand mechanism including a hand motor with a high inserting-and-extracting performance may be used to reliably release the cartridge from the locked state and extract the cartridge. Thus, although the above-described lock member seems to have a simple structure, the lock member is desirably precisely designed in consideration of the balance between the locking force and the inserting-and-extracting performance to ensure the reliability of the locking and unlocking operation.
In addition, recently, the storage capacity of a single magnetic tape cartridge has been rapidly increased. Therefore, the number of magnetic tape cartridges that are to be prepared to provide a certain storage capacity has been reduced. As a result, the sizes of the magazine and the magnetic tape library apparatus have been reduced.
Accordingly, there has been a demand for a small lock mechanism capable of reliably preventing cartridges from falling from a magazine. In addition, there has been a demand for an unlocking mechanism capable of releasing the cartridges from the locked state established by the lock mechanism without increasing the size of the library apparatus that has been reduced.